Supervisory device for telegraph apparatus



March 28, 1933- E. LIESK ET AL 1,902,964

SUPERVISORY DEVICE FOR TELEGRAPH APPARATUS Filed March 26, 1931 J 1 [79*] B B I EH 3&2: o I

I 1 I I fiyz Patented Mar. 28, 1933 UNITED STATES PAT Em oFFIcs ERwiN LIESK, 0E BERLIN, AND WILHELM KRUsE, or WILHELMSI-IAGEN NEAR BER-LIN, GERMANY, ASSIGNORS TO 0. LORENZ A. G., OF BERLIN, GERMANY SUPERVISORY DEVICE FOR TELEGRAPH APPARATUS Application filed March 26, 1931, Serial No. 525,414, and in Germany March 29, 1930.

The present invention relates to a device I for supervising telegraphic apparatus in order to indicate the continued maintenance of apreviously established connection between a calling and a called station.

It is already well known in'telegraphy and similarly related arts that special signalling means may be installed at a called telegraph station so that upon the establishment of a connection between telegraphicapparatus associated with a calling station and that associated with a called station, an answering signal is automatically sent back to the calling station in the form of letters or numbers. The single transmission of the answering signal upon the establishment of a connection with the called telegraph apparatus assures the calling station that the proper subscriber has been called and that the apparatus at that station is ready for operation, but there is no certainty that the apparatus will subsequently remain ready for reception throughout the entire period during which the connection may be desired. Often in the sending telegraphic messages very important news must be transmitted. In this case the calling subscribershould have suitable means of assuring himself that, at all times during the transmission period, the telegraph apparatus at the particular called station remains ready for reception. 1

According to the present invention this problem is'solved by having the subscriber at the calling station transmit a signal which initiates the operation of apparatus at the called station adapted to automatically send back a similar or predetermined signal, thereby indicating the readiness of the called station to continue to receive signals transmitted by the calling subscribers station. During the transmission of the answering signal the supervisory device associated with the calling subscribers station for signalling back tothe called subscribers station is automatically rendered inoperative. v

A further feature of the invention is that upon the breaking or termination of the paper tape at the receiving station the trans mission of the answering signal cannot take place.

energized its associated core .ously with An arrangement of the device embodying the invention is illustrated by way of eXam- .ple in the drawing in which Fig. 1 diagrammatically represents two tel egraphstations having connections established through central office 0 and m Fig. 2 is a perspective and diagrammatic VIEW of one modification of the supervisory device associated with a telegraph station.

In Fig. 1 two telegraph stations A and B are illustrated. They may be connected with oneeanother either by hand or automatically by way of the central station 0. At telegraph station A, S70 represents the transmitting key, EM the receiving relay, and K the answering device. At station B there is likewise shown a transmitting key S10 a receivingrelay EM and an answering device K The answering or connection indicating devices K and K are located in the spaces A and B of the telegraph apparatus A and B.

In Fig. 2 a supervisory device A is shown associated with telegraph station A.

The supervisory device A shown in Fig. 2 will now be more fully described.

The supervisory device comprises electromechanical clockwork D, which is associated with a coil M connected to the source of current represented by the current mains N Upon closing contact zthe coil M isenere gized by way of the following circuit: line a, contact 0 of the slow-release re1ay'V,-contact a, coil M and line b. When coil M is 9 is pulled into the coil M and the equal-armed lever 9 connected to 9 by pin 9 moves towards thecoil M. The equal-armed lever g is rigidly connected to the shaft e of gear 7, the gear being free-to rotate upon the shaft 6. In order to cause the core g to return toits inoperative position upon the breaking of contacts, a spring h is attached to the other end of the lever g by'means of a pin k This spring is securely suspended at its other end from a pin in. By energizing the; coil Mthe gear f is caused to mesliwith the gear i andtherefore '21 rotates. The gear -11 is keyed to the shaft K which is therefore rotated simultane- 1 gear 2'. Mounted andkeyed on the shaft K is a cam disc K cam follower I K travels on the periphery of the cam disc K This cam follower opens and closes a contact K while passing over the projecting shoulders of the cam. The projecting shoulders of the cam arearranged at such distances from each other, that upon rotation of the cam disc K they break the contact K with a sequence similar to the impulses of a pre-arranged signal in the five-unit code if that code is used for ordinary transmission;

The arrangement" is so adjusted that the cam disc K will execute only one revolution. But variations in the number of revolutions or' speed'of cam disc I 1 may occur during the operation of the mechanism. This would interfere with the correct transmission of the answering signals. Thus, care must be taken that the speed of the clock-work is synchronized with and controlled by the driving motor of the telegraph apparatus. Such control is effected by means of a small synchronizing device S, in which the rotor S is keyed to the shaft K. The synchronizing device, S

exerts a braking action if the clock-work D runs too fast and accelerates its speed if the clock-work is running too slowly. The synchronizing device S is energized'from the current mains N through a commutator C arranged on the shaft rof the driving motor common to the telegraph apparatus, by means of two sliding brushes 0 and Either alternating or direct current may be used to drive the synchronizing device S. Thus the synchronizing device S may be supplied directly from the mainsN. I

If B is the calling station and A the called station, then by depressing a particular key a predetermined combination of signals will be transmitted from the calling station E to the called station A- for the purpose of causing the clock-work D at the called telegraph station to turn shaft K.

A rod or typebar Z will be operated by this combination of signals at the desired called station. This rod is effective during its reciprocating movement to close and open the contact 2, and simultaneously with this operation of c the clock-work D causes K to rotate upon the energization of coil M. Subsequently in consequence of the action of the spring h, gear is again returned to its inoperative posltion.

As the cam disc K rigidly connected with the clock-work D through a gear transmission by way of shaft K rotates, the telegraph line in which contact K is situated, will be subjected to interruptions of current by the breaking of contact K 7 These interruptions are sent backto the calling subscriber in whose apparatus the signals are recorded.

From the above description it follows that the answering signal may be sent back at any time by the depression .of a specialkey pro vid'ed at the calling station. Thus the transmitting subscribermay assure himself at any ing station,

must be avoided. This is causes the energization of slow-release relay 7 V in the calling subscribers supervisory device, thereby opening the circuit of the calling subscribers supervisory device by way of the contact o.

The slow-release relay V is constructed in any of the ways well known in the art, so that its rapidly attracts its armature and opens the contact 4), but drops the armature off only after a considerable delay. 7 Thus, even after key contact t is opened during the run at the called station of the combination of sig nals in its associatedsupervisory device,

transmission of any part of the answering signal by the calling station will beavoided. In order to prevent the transmission of the answering signal, when the tape or paper strip has beenbroken or terminated, the tape P is run on a rail F. A light roller It connected to 'a contact spring P travels upon this tape. Belowspring P is a contact'p As soon as the paper strip breaks, the slot L in the guiding rail F is uncovered and the roller R mounted on the spring slips through. In consequence the following circuit is closed by way of the contact springs p and 19 line a, contact spring p ,;contact spring 39 winding of the slow-releaserelay V and line b. The

slow-release relay V is then energized and the contact '0 is opened. Thus, the transmission of an answering signal by the calling again only, the guiding rail F and the thereby opened.

of a calling station, a called station connected apparatus at the called thereto, supervisory station, and means at the calling station for causing said apparatus to send back station "station is prevented. The supervisory device if tape P is identification signal only if thecalled station remains conditioned for reception.

2. In a printing telegraph system, the combination of a calling station, a called station connected thereto, a plurality of type'b'ars and supervisory apparatus at the'called'station, and means at lecting and operating the type bars in response to signals transmitted from the callthe supervisory apparatusbeing the called station for se' responsive to the operationof a predeter mined type bar to send back a station identification signal only if the called station remains conditioned for; reception.

'3. In a telegraph system, the combination of a calling station and a called station connected thereto, supervisory apparatus and a,

tape recording device at the called station means at the calling station for causing said apparatus to send back an answering Signal only if the tape is in normal or unbroken condition.

4. In a telegraph system, the combination of a calling station and a called station con nected thereto, supervisory apparatus and a tape recording device at the called station, means at the calling station for causing said apparatus to send back an answering signal only if the tape is in normal or unconsumed condition.

5. In a telegraph system, the combination of a calling station, a called station connected thereto, supervisory apparatus at the called station, and means at the calling station for causing said apparatus to send back an answering signal only if the called station remains conditioned for reception, and additional means adapted to limit the number of answering signals transmitted by the supervisory apparatus.

6. In a telegraph system, the combination of a calling station, a called station connected thereto, supervisory apparatus at the called station, and means at the calling station for causing said apparatus to send back a station identification signal only if the called station remains conditioned for reception and additional means at the called station adapted to maintain the answering signals in synchronism with signals transmitted by the calling station.

7 In a telegraph system, the combination of a calling station and a called station connected thereto, supervisory apparatus and a tape recording device at each of said stations,

means at the calling station for causing the supervisory apparatus at the called station to send back an answering signal only if the called station remains conditioned for operation, and additional means at said calling station for maintaining supervisory apparatus thereat ineffective for transmitting an answering signal to the called station.

8. A teleghaph system in accordance with claim 7, characterized in this, that said additional means comprises a slow release relay operable simultaneously with said firstmentioned means.

In witness whereof We afiix our signatures. V

ERWIN LIESK. WILHELM KRUSE. 

